1. Field of the Invention
The present invention relates generally to glass windows and doors. More specifically, the present invention relates to preparing glass panels for insertion into window frames. The present invention includes methods for protecting or masking glass panes to be disposed within window frames, while leaving the peripheral region free to be better sealed within a frame.
2. Description of Related Art
Glazing panels are often mounted within frames such as window frames. The glazing panels can be single glass panes or multi-pane, insulating glass units. The window panes typically have first and second major surfaces with peripheral edges about the major surfaces, and peripheral regions within the peripheral edges. The peripheral regions bound a central region on each of the first and second major surfaces. The glass panes are typically ultimately disposed within frames, where the frames are dimensional and configured to accept only the peripheral regions of the glass panes, leaving the central regions of the window panes unoccluded. In some uses, the window panes are first formed into insulating glass units, having two or more substantially parallel window panes separated by spacers there between. In some insulating glass units, the parallel glass panes are sealed to the spacing member, and the air between the panes replaced with an inert gas. The resulting insulating glass unit can then be disposed within a window frame.
Old style windows were often made using several smaller panes of glass held within smaller frames, which were joined together into one window unit. Each portion of a double hung window might be formed of 4, 6 or 8 window panes held in place within a corresponding number of window frames. The additional frame members typically required additional glazing to secure the multiple window panes to the frame. The additional glazing represented additional labor and additional opportunities for air infiltration. Modern windows are typically formed of larger single panels, which are often insulating glass units. Some purchasers desire the older style appearance, but without the drawbacks. To achieve these goals, modern windows can have muntin bars placed over the single glass panels, to achieve the older style appearance of multiple panes, but without the disadvantages. The muntin bars thus represent another set of framing members to be disposed over the glass surface.
It is common for the glass panes and insulating glass units to be formed at one location, protected in some fashion, and shipped to another location. It is not until arrival at the second location that the glass panes or insulating glass units are mounted within window frames. Muntin bars may also be mounted at the second location The window frames are often then shipped to a third location, where they may be installed within homes, buildings, or automobiles.
There is an opportunity for damage to the glass panes at many points in the process, including the transport to the second location prior to framing, and subsequent to framing, prior to arrival at the building site. The glass major surfaces may also be damaged after installation in the building, for example, during building construction.
For the above-stated reasons, the glass pane major surfaces are often masked, for example, with a polymeric protective film. The protective film can provide some protection from abrasion and scratches to the surface during the transport or the building construction.
Sheets of masking material may be adhered to one or more of the glass pane surfaces to protect the surfaces from the scratching previously mentioned. Often, the entire glass pane is masked on at least one major surface. The masking material may be cut to the same size as a glass pane major surface. The glass pane may then be inserted within a window frame adapted in dimension to accept the peripheral region of the glass pane within the window frame. This can be done while the masking material is in place, leaving the glass major surface protected. This method, however, can leave polymeric material trapped along the peripheral region of the glass pane, between the glass surface and the enclosing frame member. The visible polymeric remnants may be unsightly, and may eventually degrade and/or be pulled out, reducing the integrity of the seal between the glass surface and the enclosing window frame. This can leave a gap between the glass surface and the window frame.
Cutting knives have been used to mechanically cut through the polymeric masking material while the masking material is on the glass surface. The peripheral strip of masking material thus delineated from the central region masking material may be peeled off, leaving the protected central region intact. The knife blade used to cut through the polymeric material may require an undue amount of adjustment, and may not provide exactly the needed pressure to cut through the polymeric film but not into the window pane. As windows are increasingly covered with coatings, the knife edge cutting through the outermost window coating can be very undesirable. What would be desirable are methods for removing the masking material that do not requiring touching the glass pane adhered to the masking material.